Millions poured into keeping Melbourne’s oldest trains on track

The Victorian state government is spending $75 million to keep Melbourne's oldest trains on the tracks.

The “Comeng” trains have been the workhorses of the suburban fleet since rolling out of the Dandenong factory in 1981.

Metro Trains engineers have spent two years developing a new interior design, which includes more hand holds, better lighting, upgraded seats and covered walkways between carriages.

A test train is currently being evaluated on the network, with 70 percent of the fleet expected to be refurbished within the next two years.

The state government will spend $75 million to keep the city's oldest trains on the tracks. (9NEWS)Public Transport Users Association spokesman Daniel Bowen said the government appears to have learned from the botched withdrawal of Hitachi trains early last decade, when it was forced to buy back scrapped carriages to cope with overcrowding.

“It does make sense this time around to upgrade the Comeng fleet and keep them running for a while,” Mr Bowen said.

Transport Minister Jacinta Allan wouldn’t be drawn on how long the government plans to keep the aging trains on the tracks.

“We’ll be guided by the advice from engineers as to how long the service of each train runs for," she said.

“We know that these trains can continue to provide a good service, they can continue to provide a safe service.

“We also want to make sure they can provide a comfortable service for passengers”.

Comeng trains will progressively be replaced by new High Capacity Metro trains on the Pakenham and Cranbourne lines from mid-2019, but will continue to run on the Frankston, Sandringham, Werribee, Craigieburn, Upfield and Sunbury lines.